The investigator hypothesize that the combined use of (1) non-invasive biomarkers in peripheral blood predicting anti-donor immunological activation or quiescence (2) interactive and actionable data analytics delivered at the bedside will promote safe clinical follow-up of kidney transplant patients with less need for invasive and induced risk surveillance by allograft protocol biopsies to assess allograft rejection in clinically stable kidney transplant patients. It is therefore proposed an European, multicenter, prospective randomized comparing two strategies of follow-up: in the first, biopsies are guided by biomarkers, in the second one, a routine biopsy is performed at M3. In both groups, a biopsy is performed at M12 and whenever considered necessary by the clinician.

The main objective of this study is to demonstrate the ability of use of non-invasive biomarkers to decrease the number of allograft biopsies during the first year after transplantation. 300 new transplanted patients in the 7 clinical transplant sites will be included in the prospective multicentre EU-TRAIN Impact study with centralized storage of samples in CHUN (blood mRNA), ICS (blood cellular assays), Saint -Louis Hospital (blood anti-HLA DSA, and non-HLA antibodies), INSERM (Biopsy mRNA). Recruitment of patients will start on the day of transplantation (d-8 for transplantation from living donors) and data/samples collected over the first year following transplantation. Realization of all the acts for the research are representing the usual medical practice (Standard Of Care: SOC) except six additional blood samples that will be collected and analyzed specifically for the research and additional analysis done specifically for the research on half of one of the two biopsy cores from the recipient. 3 additional blood samples from the living donor will also be collected and analyzed specifically for the research (timepoint of the sampling: anytime from 8 days to the day of transplant.

Inclusion Criteria:

1. All men and women, age ≥18 years old.
2. Subject must be a recipient of a single renal transplant from a deceased or living donor.
3. Subject is willing and able to provide signed written informed consent and willing to comply with study procedures
4. Women of Childbearing Potential (WOCBP) must be using an adequate method of contraception to avoid pregnancy throughout the study in such a manner that the risk of pregnancy is minimized. WOCBP include any female who has experienced menarche and who has not undergone successful surgical sterilization (hysterectomy, bilateral tubal ligation, or bilateral oophorectomy) or is not postmenopausal [defined as amenorrhea ≥ 12 consecutive months; or women on hormone replacement therapy (HRT) with documented serum follicle stimulating hormone (FSH) level > 35 mIU/mL]. WOCBP must have a negative serum or urine pregnancy test (minimum sensitivity 25 IU/L or equivalent units of HCG) within 72 hours prior to the start of clinical trial

Exclusion Criteria:

1. Subject with Hepatitis B chronic infection and/or active infection by Hepatitis C virus (positive blood PCR result at the moment of transplant).
2. Subjects with known human immunodeficiency virus (HIV) infection.
3. Patients with active systemic infection that requires the continued use of antibiotics.
4. Patients with neoplasia except localized skin cancer receiving appropriate treatment.
5. WOCBP who are unwilling or unable to use an acceptable method to avoid pregnancy for the entire study period, women who are pregnant or breastfeeding or women with a positive pregnancy test on enrolment.
6. Subjects who are legally detained in an official institution.
7. Primary non-function or early graft loss due to mechanical/surgical complications.
8. Death within the first 6 months after transplantation.
9. Any condition that, in the opinion of the investigator, might interfere with the patient's participation in the study, poses an added risk for the patient, or confounds the assessment of the patient
10. History of multi-organ transplant (interference with rejection natural history).